Long-term goals (within a company)

A few months ago I got a new job as a senior software engineer and my engineer manager has asked me to talk about my long-term goals regarding my career. Now, I'm 30 years old, and my long-term goals (and even my short-term goals for the next 5 years) are not related at all to the company I'm working for; my goals are not related to any company at all: my goal/dream is to have my own small company where I work on products I do care about using sane and boring tech. The only reason I work for companies as a software engineer is: money, learning (although I do learn more and better at my own pace in my free time), and yes, money again.

Obviously, I can't say this to my manager! While I appreciate learning about new hot stuff like K8s and the like, I find it miserable to work with such technologies. I can handle it, and I'm productive, but I don't think I will be able to handle it when I'm 40. Also the management path is not for me. I like programming, I appreciate well-crafted software and I like the idea of working on products that are actually useful and respect the user/customer (even if that means less money at the end of the day). That's why I want to have my own company. That's my goal for the next 5, 10, 20 years. I cannot come up with something to tell my manager that is not a blatant lie. I wish I could say "I appreciate your help, manager, but don't ask me about my long-term goals. As a good professional all I can promise is: to behave like a professional regarding the quality of my job, being honest and stick to the deadlines".